Ron Guth:
In 1808, mint employees took an old, unused die from 1807, punched an 8 over the 7, and began striking coins. The result is Overton 101, the only overdated die variety of 1808. The overdate is clearly visible, with the serif of the 7 visible on the left side of the top of the final 8; the horizontal bar and diagonal stem of the 7 can be seen inside the 8.

This is a common variety that can be found in nice condition up to, and including, MS65. The PCGS CoinFacts Condition Census of the ten best examples of this date includes nine examples that are MS64 or better, with MS65 being the best available grade.